One-stage reconstruction of post-electrical burn forearm and hand defects using microsurgical transfer of an ulnar neuromyotendinocutaneous unit

Epirubicin is known to be metabolized in the liver. Therefore, drugs such as cimetidine, which inhibit the cytochrome P-450 enzyme system or reduce liver blood flow, may reduce the plasma clearance of epirubicin. In a small study, epirubicin 100 mg/m2 every 3 weeks was administered intravenously to eight patients, who also received oral cimetidine (400 mg b.d. for 7 days starting 5 days before chemotherapy) with either the first or second cycles. Epirubicin pharmacokinetics and liver blood flow (idocyanine green clearance) were assessed at each course. The areas under the plasma concentration time curves (AUCs) were used to compare the systemic exposure to epirubicin and its metabolites with each course. The estimated median percentage increase (95% confidence interval CI) in the AUC with cimetidine were: epirubicin 50% (95% CI -18 to 193, epirubicinol 41% (95% CI 1 to 92). Despite the small numbers studied, the increase in the active metabolite epirubicinol was significant (P < 0.05). These changes in exposure were not explained by reduced cytochrome P-450 activity as the 7-deoxy-doxorubicinol aglycone AUC was not reduced (357% increase: 95% CI 17 to 719) or by a decrease in liver blood flow (17% increase: 95% CI -39 to 104). Cimetidine is likely to be coprescribed or self-administered with epirubicin and therefore clinicians should be aware of this potential interaction.     

Control of microvascular resistance in physiological conditions and reperfusion

Regulation of coronary microvascular resistance is not distributed uniformly, but varies across different segments of the vasculature. Differences in regulatory mechanisms, including metabolic, myogenic, alpha-adrenergic and endothelial cell mediated, help define a series of coronary vascular microdomains. Generally, small arterioles, those less than 100 microns in diameter, respond differently than large arterioles or small arteries. This segmental distribution suggests an integrative hypothesis of regulation whereby a variety of mechanisms play a role in the overall response. One pathology that disturbs these control mechanisms in the microcirculation of the heart is reperfusion injury. Reperfusion injury of the microcirculation has as its primary target the vascular endothelium. The mechanisms responsible for reduced endothelium-dependent relaxation, likely include a reduction in the levels of tetrahydrobiopterin, a co-factor of nitric oxide synthase. Manipulation of levels of tetrahydrobiopterin in endothelial cells may be beneficial in the prevention of the pathophysiological sequelae of reperfusion injury in the coronary microcirculation.     

Pharmacokinetics of single oral doses of feprazone in patients with rheumatoid arthritis or with impaired renal clearance

1. The pharmacokinetics of feprazone have been studied in 10 patients with rheumatoid arthritis (RA), and in a further six patients with renal impairment (RI) who were not suffering from rheumatoid disease. 2. For RA patients, the mean elimination half-life (t1/2) of feprazone after a single oral dose was 21 +/- 5 h (SD), the mean apparent clearance (Cl) was 0.012 +/- 0.009 l/h per kg, and the mean apparent volume of distribution (Vd) was 0.33 +/- 0.17 l/kg. Corresponding values for RI patients were 25 +/- 13 h, 0.016 +/- 0.011 l/h per kg, and 0.46 +/- 0.24 l/kg, respectively. 3. These results show no impairment of the elimination of feprazone in RA or RI patients; Vd and Cl are greater than in healthy young volunteers or elderly subjects, the AUC values are lower, but t1/2 values are similar in all groups. 4. It is suggested that the greater Cl and Vd, and lower AUC, in RA and RI patients may be due to renal insufficiency and decreased plasma protein binding of feprazone and its metabolite, or to induction of glucuronyl transferase activity by the prior medication, thus enhancing the formation of the major metabolite, the C(4)-glucuronide, and increasing drug elimination.     

Urgent bedside endoscopic nasobiliary drainage without fluoroscopic monitoring

Emergency endoscopic nasobiliary drainage was performed successfully in 2 patients with severe cholangitis and septic shock without the help of fluoroscopy because of technical problems in the fluoroscopy units. Definitive procedure was performed after the recovery. Nasobiliary drainage can be performed without fluoroscopic guidance, but should be attempted in exceptional situations.     

Time-dose-fractionation in radioimmunotherapy: implications for selecting radionuclides

As currently practiced, the doses delivered to tumors in radioimmunotherapy are less than desirable primarily because of dose-limiting bone marrow toxicity, thus reducing the therapeutic efficacy of this modality. The biological effectiveness of internal radionuclide therapy depends on the total dose, the rate at which it is delivered, and the fractionation schedule of the radiolabeled antibodies administered. A new approach, based on time-dose-fractionation (TDF), which has been used in conventional radiotherapy, is advanced. This approach incorporates differences in dose rates, biological half-lives of the antibodies, physical half-lives of the radionuclides employed and the total doses needed for a given biological effect. The TDF concept is illustrated with several relevant examples for radioimmunotherapy. Based on the TDF approach, it is proposed that under certain biological conditions radionuclides with physical half-lives that are 1-3 times the biological half-life of the radiolabeled antibodies in the tumor are more likely to deliver sterilization doses to tumors than the shorter-lived nuclides presently in use unless precluded by specific activity considerations. Several radionuclides that meet this criteria are suggested with 32P being the most promising among them. Finally, a practical method for treatment planning in radioimmunotherapy using TDF factors is recommended.